Facile one-pot synthesis and solution behavior of poly(acrylic acid)-block-polycaprolactone copolymers

A metal-free protocol to obtain poly(acrylic acid)-block-polycaprolactone diblock copolymers (PAA-b-PCL) by a one-pot method involving simultaneous Reversible Addition-Fragmentation Chain Transfer (RAFT) and Ring Opening Polymerization (ROP) processes is reported. The strategy is based on the use of diphenyl phosphate (DPP) as catalyst and a bifunctional compound that acts as both chain transfer agent (CTA) in the acrylic acid RAFT polymerization process and co-initiator in the ε-caprolactone (ε-CL) ROP process. PAA-b-PCL diblock copolymers were obtained with near quantitative conversions of both monomers in a relatively short period of time. In aqueous solutions, PAA-b-PCL diblock copolymers self-assembled into pH- and ionic strength- responsive micellar structures.